engine doesn't want to start while choked cold

[Humboldtsailor]

for some reason my engine starts up better without the choke pulled. when i do try and choke the carb it sputters and blows gas and white smoke from the flame arrestor. I'm hoping to figure this out so i can get a more reliable start clean start. as is it starts without the choke just a little ruff for 20 seconds or so. Pulled some plugs and they do look sooty however that was after a while of trying to start the engine with engine choked. any help would be appreciated
thanks

[Nanook]

Maybe a stuck intake valve? It's easy enough to pull the valve cover plate and turn the engine over by hand. It'll be pretty obvious if one or more aren't moving.

[ndutton]

Sounds like the mixture is massively rich. If it can't be adjusted out the carburetor is due for disassembly and clean up, double check the floats for leakage and level while you're in there.

[Humboldtsailor]

yea i guess it could be a rich mix i have it set to the recommended 1.5 turns of the seat ill try turning it out half a turn. Little more in of on the engine fresh rebuild block was cracked but repairs by my machinist. rebuilt the carb with a kit from host. The carb however it was very dirty soaked it in chem-dip for a couple hours to clean. thanks

[JOHN COOKSON]

Sounds like the mixture is massively rich. If it can't be adjusted out the carburetor is due for disassembly and clean up, double check the floats for leakage and level while you're in there.

Agree. You are running way, way to rich. Is fuel pooling in the throat of the carburetor after the engine has not been started for awhile or overnight? Careful here. Be sure and monitor the engine space for gas fumes until you get this straightened out. There may be no fumes at the moment but with this sort of rich running who knows what could be next.
If there is still backfiring through the carburetor after you get the rich running straightened out do a compression check. One of the intake valves may be sticky and open or slightly open when the cylinder fires.

TRUE GRIT

[lat 64]

This is a recent rebuild, right?

Has it run well at all yet or is this still the first attempt at startup??
What I'm getting at is; a whole laundry list of issues can be guessed at if something was not put together correctly.

My list of suspects here is listed in order of easiest-to-fix first:

1. confirm choke is opening/closing all the way
2. ignition timing(not really likely IMHO. This is so easy to get wrong, but it just doesn't fit your complaint)
3. float valve is stuck open or set wrong
4. bad gas (does it smell like Uncle Roy's eighteen-wheeler?)
5. stuck intake valve or adjusted waaay too tight
6. and now for the serious boo boo; cam timing is off

I'd need more data about the work done and your progress right up to startup to do much more speculation. Just guessing now.

Remember, carbs are tricky things. All the circuts have to be open(clean) and adjusted for it to work well. Many times I have "rebuilt" a carb and introduced new problems by not checking EVERY orifice and setting.

Hope this is something more simple for you,


Russ

[tenders]

Another possibility to think about: plug wires on distributor in wrong order. With the engine running, check that the wires are going around the distributor cap in 1-2-4-3 order. If that's good, pull the wires off one at a time and see if one or more cylinders isn't contributing to the process. That will help identify a stuck valve.

[lat 64]

Another possibility to think about: plug wires on distributor in wrong order. With the engine running, check that the wires are going around the distributor cap in 1-2-4-3 order. If that's good, pull the wires off one at a time and see if one or more cylinders isn't contributing to the process. That will help identify a stuck valve.

Doh!! I missed that one.
Good catch T.

R

[Humboldtsailor]

it was the plug wire..... i feel like an idiot must have looked at those wires ten times I'm surprised it even ran as well as it did. thanks guys for your time. Thanks Tenders you got it right glad it wasn't the cam timing